Lightning-arrester.



No. trasse.

atented April 12, 1904.y

PATENT OEEICE.

GARRISON BABCOCK, OF CHICAGO, ILLINOIS.

LIGHTNING-ARRESTER.

SPECIFICATION forming part of Letters Patent No. 757,388, dated April 12, 1904. Application filed September 20, 1902*. Serial N 124,164. (No model.)

To all whom it may concern:

Be it known that I, GARRIsoN BABoooK, of Chicago, Cook county, Illinois, have invented certain new and -useful Improvements in Lightning-Arresters, of which the following is a specification. Y

This invention relates to appliances for protecting telephone or other electrical instruments and circuits from injury by destructive currents of high potential; and the object of the invention is to provide means for grounding the line in case it should become charged with atmospheric electricity from a passing storm or become crossed with a light or power wire conducting aheavy illuminating or power current, either of which intrusive currents if discharged into the line and allowed to enterv an instrument or circuit would seriously damage if not destroy it.

A further object is to provide arresters to be placed in the main line near the instrument and cable-box and which may be` used or not, as preferred, in connection with a certain central -oiiice or switchboard arrester shown and described in a companion application for Letters Patent of the United States executed on the 8th day of September, 1902.

Other objects of the invention will appear from the following detailed description.

The invention consists generally in fixed ground and line plates having their contiguous or abutting surfaces provided with ribs or corrugations meshing one with another and presenting a maximum surface with dischargepoints for the electrical current and a fusewire pressed into said corrugations and provided with a `covering of suitable insulating material, the terminals of said fuse-wire being connected in series with the circuit or instrument.

Further, the invention consists in providing a strip of insulating material, such as` silk, inclosing the fusible w1re 1n one formy of arrester and used without the fusible wire in the other and placed between the line and ground plates and pressed into the corrugations thereof, assuming a zigzag or serpentine form therein and normally acting as a non-conductor between said plates, but carbonizable by a high-potential current to close the ground-circuit when the line is opened by the fusing of the resistance-wire.

Further, the invention consists in various constructions and combinations, all as hereinafter described, and particularly pointed out in the claims.

In the accompanying drawings,forming part of this specification, Figure 1 is a longitudinal vertical section of a lightning-arrester designed particularly for use between the line and cables and conductors or in series with circuits or instruments. Fig. 2 is a plan view of the same. Fig. 3 is a View with the lineplate and the upper half of the insulatingcovering removed, showing the position of the fuse-wire between the corrugations of the plates. Fig. 4 is a longitudinal vertical section of a lightning-arrester designed for use on the line near the instrument, usually a telephone. Fig. 5 is a plan view of the same. Fig. 6 is a section on the line 'fr m of Fig. 4.

In the drawings2 represents a base of'any suitable non-conducting material, preferably wood, having at one end a metallic block 3, provided with a binding-screw 4, between which and said block the line-wire 5 is secured.

6 and 7 are clips between which a fiat plate 8 is inserted and having a slot 9 to allow it to straddle a binding-screw 10,wl1ich secures the plates to said block 3.

11 is a conducting block or plate,preferably carbon, which I will hereinafter designate as the ground carbon block or plate, secured to the base by any suitable means, preferably by a bolt or screw ll', and havingaground-wire 1'1", provided in its upper surface with a series of transverse flutes, ribs, or corrugations l2, that mesh or cojact with a corresponding series of corrugationsin ay carbon plate 13, which I will hereinafter refer to as the line carbon plate. These ribs or corrugations, as described yin the companion application referred toabove,

materially increase the area of the contiguous surfaces of said plates without increasing their length or breadth, while the edges of the ribs or corrugations serve as eflicient discharge- N points for the electrical current. The line carbon plate in this form of arrester is fixed to distinguish it from the corresponding platev shown in the companion application above re- TO0 ferred to, and I prefer to provide a holder 14 for said plate having depending wings or guideways l5, between which said plate is slipped', and said holder being provided with an arched portion 16, which rises above the top of said plate and is engaged by an arm 17 on a stud 18, that has a threaded lower end to enter the base 2 and by means of which the holder is firmly held and the line carbon plate pressed down upon the ground-plate beneath. By revolving the stud 18 the arm 17 can be swung to one side away from the holder to allow the removal of the line-plate for examination or repairs. The holder 14 at its end adjacent the line is provided with an upwardlyturned end 19, thatis engaged by a spring-arm 20 on the clip 6. Between the carbon plates I provide a retardation fusible wire 21, preferably of soft-metal composition or German silver,having its line-terminal connected to the plate 8 and the other terminal connected toa corresponding plate that is secured between a set-screw and a block 22, provided at the opposite end of the base from the line-wire. A wire 23 to the same circuit is also secured between a set-screw and block 22. The fusewire 21 is extended from side to side of the carbon plates and pressed in between the corrugations thereof and being of considerably greater length than a straight wire between the plates 8 offers in consequence a much greater resistance and has a greater retarding effect on a high-tension trespassing current entering the arrester from the line. The fuse-wire 21 is preferably iattened to present a greater surface to the carbon plates and also to allow them to be pressed nearer together. To prevent short-circuiting of the comparatively feeble current passing over the line in the daily use of the system, I provide a covering 24 for the wire of suitable insulating material, preferably silk, extending between the plates 8 and the full width of the carbon plates and inclosing the wire and separating the corrugated surface of one plate from the corresponding surface of the other. This silk covering while normally being a non-conductor will when the `wire is fused by the entrance of ahighpotential current into the arrester and the heating of the carbons become carbonized and form a conductor between the carbon plates and ground any intrusive current that may enter from the line on account of its becoming charged with atmospheric electricity or crossed with a light or power wire conducting heavy illuminating' or power currents. This grounding of the high-tension or destructive transient currents that may from time to time become accidentally discharged into the line-wire will open the line to the circuit or instrument and prevent its damage or destruction.

In Figs. 4 and 5 Ihave shown a form of arrester designed for use in connection with an electrical instrument, such as a telephone.

This appliance is similar tothe one above described except that the base is a little shorter, owing to the fact that a connection for the line-wire only is required thereon, the arrester being cut into the line near the instrument, and when the circuit is closed through the arrester it forms a shorter cut to the ground for the current and along a line of less resistance than by following along' the wire to the instrument. In this form of arrester the fixed ground and line carbon plates are provided as before,but the serpentine fuse-wire is omitted, and in place thereof I provide merely the insulating-strip between and pressed into the corrugations of the carbon plates. This insulating material normally acts as a non-conductor to open the circuit between said plates except when the line is charged with atmospheric electricity or crossed with a light or power wire, at which time the heavy current entering the arrester will carbonize the silk nonconducting material and transform it into a conductor that will close the circuit between the carbon plates and ground the line, preventing damage to the circuit or instrument. In the former arrester the fusible retardationwire between the plates and pressed within the corrugations thereof is of much greater length than the wire usually employed for this purposeand offers in consequence greater resistance to the heavy current from the line. The ridges or corrugations in the surfaces of the carbon plates facilitates the grounding of high-potential current-s, as the contiguous surfaces of the plates are considerably increased in area and provided with discharge-points. The above applies also to the arrester where the fusible wire is omitted, the device being cut into the line, the other connection being to the ground.

I claim as my invention-- 1. In a lightning-arrester, fixed line and ground carbon plates, a fusible retardationwire between said plates and having its terminals connected respectively in series with the circuit or instrument and provided with a suitable insulating-covering, substantially as described.

2. In a lightning-arrester, fixed line and ground carbon plates having transverse corrugations or ribs in their contiguous surfaces, a serpentine retardation fuse wire pressed within said corrugations and having its terminals connected respectively in series with the circuit and instruments, and an insulating-covering for said fuse-wire.

3. In a lightning-arrester, the combination, with a base of non-conducting material, of a carbon plate having' a ground connection secured to said base, a line carbon plate, a inetalic holder therefor, said line and ground carbon plates having' corrugated contiguous surfaces, a retardation fuse wire pressed within said corrugations and insulated from said plates and having its terminals connected IOO I'IO

respectively with the line and cable, a stud having a threaded end to enter said base, and an arm to overhang and engage said holder and press said plates together, substantially as described.

4f. A safety device for electric circuits, comprising fixed line and ground plates, a fusible retardation wire interposed between said plates and extending zigzag from side to side thereof, and an insulating-covering for said wire.

5. A safety device for electric circuits, comprising fixed line and ground plates having roughened contiguous surfaces, a fusible retardation-wire interposed between said plates and pressed into the depressions therein, and an insulating-covering for said wire.

6. A safety device for electric circuits, cornprising xed line and ground plates, a fusible retardation wire interposed between said plates, and a strip of insulating material carbonizable by a heavy current separating said wire and plates.

7. A safety device for electric circuits, comprising fixed line and ground plates having corrugated or fiuted surfaces, a fuse wire serpentine in form interposed between said plates and pressed into the depressions or iiutes therein, and an insulating-strip of textile material separating said wire and plates and adapted to be broken down and carbon; ized by a current of high potential and close the ground-circuit through said plates when said wire is fused.

8. A safety device for electric circuits, comprising fixed line and ground plates, a fusible retardation-wire arranged between said plates in the line-circuit and extending zigzag from side to side of said plates, and an insulatingstrip of textile material normally supporting and insulating said wire and plates and adapted to be carbonized and made a conductor by a current of high potential and close the circuit through said ground-plate when the linecircuit is opened by the fusing of said retardation-wire.

In testimony whereof I have hereunto set my hand this 10th day of September, 1902.

GARRISON BABCOCK.

In presence of- IRA S. READ, G. E. KNIGHT. 

